|
Other common
name(s): lapachol, lapacho, lapacho morado, lapacho
Colorado, ipe roxo, ipes, taheebo, tahuari, trumpet bush, trumpet tree
Scientific/medical
name(s): Tabebuia
impetiginosa, Tabebuia avellanedae, Tabebuia heptaphylla, Tabebuia
ipé
Description
Pau d'arco is a large tree that grows naturally in the
rainforests of Central and South America. It may be cultivated in
southern Florida. There are about 100 species of the tree, which
produces large flowers and can grow to 150 feet tall and 6 feet in
diameter. Tebebuia
impetiginosa produces purple or pink flowers, while other
varieties produce yellow or white flowers. The inner bark of the tree
is used in herbal remedies.
Overview
Laboratory and animal studies suggest that lapachol and other
compounds extracted from or made from pau d'arco may have some effects
against certain illnesses. However, available evidence from
well-designed, controlled studies does not support this substance as an
effective treatment for cancer in humans. Pau d'arco also has
potentially dangerous side effects.
How is it promoted for use?
Pau d'arco is promoted as a cure for dozens of illnesses and
medical conditions, including arthritis, ulcers, diabetes, and cancer.
Proponents also claim that, when taken internally, pau d'arco relieves
infections, reduces inflammation, promotes digestion, strengthens the
immune system, flushes toxins from the body, and protects against
cardiovascular disease and high blood pressure. Proponents also use it
to treat lupus, osteomyelitis, Parkinson's disease, psoriasis, and to
relieve pain. Some use the boiled bark externally as a poultice or use
the strained liquid as a wash to treat skin inflammations, fungal
infections, hemorrhoids, eczema, and wounds.
What does it involve?
Pau d'arco is available as a capsule, tablet, salve, liquid
extract, powder, and tea from health food stores and over the Internet.
Recommended dosage varies by manufacturer. When making tea,
practitioners say the bark must be boiled or simmered for at least 8
minutes to release the active ingredients, which do not dissolve easily
in water.
What is the history behind it?
Tea made from pau d'arco is thought to have been popular among
the ancient Incas and natives of the South American rain forests, who
used it to cure disease and as a tonic to strengthen the body and
improve overall health. Caribbean folk healers reportedly use the leaf
and the bark to treat backaches, toothaches, and sexually transmitted
diseases. The native tribes of Brazil used the tree to make bows for
hunting. When the Portuguese colonized Brazil, they named the tree pau
d'arco, which means "bow stick." The herb remains a popular Brazilian
folk remedy.
New interest in pau d'arco arose in the mid-1960s, when a
Brazilian physician claimed that the substance could relieve pain,
increase the number of red blood cells, and cure numerous illnesses,
including cancer. Since the early 1980s, the herb has been sold in
health food stores in the United States, where it is promoted as a
treatment for virtually every kind of medical complaint.
What is the evidence?
One of the active ingredients in pau d'arco that has been
studied is called lapachol. In laboratory animals, lapachol was found
to be effective against malaria and certain kinds of animal tumor
cells, such as sarcoma, but it did not have an effect against other
kinds of cancer, including leukemia and adenocarcinoma. Further studies
are required to determine whether these results apply to humans.
There have only been a few studies on lapachol in humans. An
uncontrolled study sponsored by the National Cancer Institute in the
early 1970s found no toxic effects on liver or kidney tissue. However,
lapachol did prevent blood from clotting, and doses thought to be high
enough to affect tumors posed a serious risk of bleeding. Clotting
function returned to normal when the drug was stopped. Based on these
results, approval for lapachol as a new anticancer drug was not sought.
Research in the area was discontinued. Canada subsequently banned the
substance in 1985.
Pau d'arco contains at least 20 active compounds, including
naphthaquinones (of which lapachol is one), anthraquinones, alkaloids,
quercetin, and other flavonoids whose effects are not fully known.
Unconfirmed tests showed that crude extracts of the tree bark
stimulated the activity of immune system cells called macrophages. The
substance also killed lung cancer cells and liver cancer cells grown in
test tubes and reduced the rate of lung cancer spread in mice after
surgery to remove the initial tumor. The bark extract also may kill
bacteria or fungi. In a 2004 study, 2 compounds made from
naphthaquinones showed promise in animal studies for malaria treatment.
It is important to note, however, that studies of extracted compounds
would not be expected to yield the same results as studies of the raw
bark.
Are there any possible problems or
complications?
This product is sold as a
dietary supplement in the United States. Unlike companies that produce
drugs (which must provide the FDA with results of detailed testing
showing their product is safe and effective before the drug is approved
for sale), the companies that make supplements do not have to show
evidence of safety or health benefits to the FDA before selling their
products. Supplement products without any reliable scientific evidence
of health benefits may still be sold as long as the companies selling
them do not claim the supplements can prevent, treat, or cure any
specific disease. Some such products may not contain the amount of the
herb or substance that is written on the label, and some may include
other substances (contaminants). Though the FDA has written new rules
to improve the quality of manufacturing processes for dietary
supplements and the accurate listing of supplement ingredients, these
rules do not take full effect until 2010. And, the new rules do not
address the safety of supplement ingredients or their effects on health
when proper manufacturing techniques are used.
Most such
supplements have not been tested to find out if they interact with
medicines, foods, or other herbs and supplements. Even though some
reports of interactions and harmful effects may be published, full
studies of interactions and effects are not often available. Because of
these limitations, any information on ill effects and interactions
below should be considered incomplete.
Pau d'arco has some potentially serious side effects. Some of
the chemicals in pau d'arco, such as hydroquinone, are known to be
toxic. High doses taken internally may cause liver and kidney damage.
In animal studies, birth defects and deaths occurred among rats whose
mothers were given lapachol during pregnancy. Pau d'arco should be
avoided, especially by women who are pregnant or breastfeeding.
Even low doses of pau d'arco can cause dizziness, nausea,
vomiting, and diarrhea and can interfere with blood clotting. The
resulting bleeding can cause anemia. In addition, pau d'arco, when
taken by mouth, can interact with aspirin and blood-thinning
medications, further increasing the risk of bleeding. It may also
increase the risk of bleeding in people with hemophilia or other
clotting disorders.
The bark of the tree can sensitize skin and has caused asthma
in work settings where people are exposed to the wood dust. Allergic
reactions are possible.
Twelve commercial pau d'arco products that were tested in
Canada showed that only one contained lapachol, which normally makes up
about 7 percent of pau d'arco, suggesting the products likely contained
other substances.
The potential interactions between pau d'arco and other drugs
and herbs should be considered. Some of these combinations may be
dangerous. Always tell your doctor and pharmacist about any herbs you
are taking. Relying on this type of treatment alone and avoiding or
delaying conventional medical care for cancer may have serious health
consequences.
Additional Resources
More information from your American Cancer
Society
The following information on complementary and alternative
therapies may also be helpful to you. These materials may be found on
our Web site (www.cancer.org)
or ordered from our toll-free number (1-800-ACS-2345).
References
Algranti E, Mendonca EM, Ali SA, Kokron CM, Raile V.
Occupational asthma caused by Ipe (Tabebuia spp) dust. J Investig Allergol Clin Immunol.
2005;15:81-83.
American Cancer Society. Questionable methods of cancer
management: ‘nutritional' therapies. CA Cancer J Clin.
1993;43:309-319.
Cassileth BR. Evaluating complementary and alternative
therapies for cancer patients. CA
Cancer J Clin. 1999;49:362-375.
de Andrade-Neto VF, Goulart MO, da Silva Filho JF, da Silva
MJ, Pinto Mdo C, Pinto AV, Zalis MG, Carvalho LH, Krettli AU.
Antimalarial activity of phenazines from lapachol, beta-lapachone and
its derivatives against Plasmodium falciparum in vitro and Plasmodium
berghei in vivo. Bioorg
Med Chem Lett. 2004;14:1145-1149.
Dinnen RD, Ebisuzaki K. The search for novel anticancer
agents: a differentiation-based assay and analysis of a folklore
product. Anticancer Res.
1997;17:1027-1033.
Felício AC, Chang CV, Brandão MA, Peters
VM, Guerra Mde O. Fetal growth in rats treated with lapachol. Contraception.
2002;66:289-293.
Fetrow CW, Avila JR. Professional's
Handbook of Complementary & Alternative Medicines.
Philadelphia, PA: Lippincott Williams & Wilkins; 2004.
Montbriand MJ. Past and present herbs used to treat cancer:
medicine, magic, or poison? Oncol
Nurs Forum. 1999;26:49-60; quiz 61-62.
Pau darco. Drug Digest Web site.
http://www.drugdigest.org/DD/DVH/HerbsWho/0,3923,552793|Pau+D%27arco,00.html.
Accessed June 6, 2008.
Pau d'arco. Memorial Sloan-Kettering Cancer Center Web site.
http://www.mskcc.org/mskcc/html/69325.cfm. Updated January 8, 2008.
Accessed June 6, 2008.
Pau d'arco/taheebo tea/lapacho/lapacho morado/ipe
roxo/ipe/trumpet bush. BC Cancer Agency Web site.
http://www.bccancer.bc.ca/HPI/UnconventionalTherapies/PauDArco.htm.
Updated February 2000. Accessed June 6, 2008.
US Congress, Office of Technology Assessment. Unconventional
Cancer Treatments: OTA-H-405. Washington, DC: US Government Printing
Office; 1990.
Woo HJ, Choi YH. Growth inhibition of A549 human lung
carcinoma cells by beta-lapachone through induction of apoptosis and
inhibition of telomerase activity. Int
J Oncol. 2005;26:1017-1023.
Woo HJ, Park KY, Rhu CH, Choi BT, Kim GY, Park YM, Choi YH.
Beta-lapachone, a quinone isolated from Tabebuia avellanedae, induces
apoptosis in HepG2 hepatoma cell line through induction of Bax and
activation of caspase. J
Med Food. 2006;9:161-168.
Note: This information may not cover
all possible claims, uses, actions, precautions, side effects or
interactions. It is not intended as medical advice, and should not be
relied upon as a substitute for consultation with your doctor, who is
familiar with your medical situation.
Last Medical Review: 11/01/2008
Last Revised: 11/01/2008
|
